Preformed roof ventilation system

ABSTRACT

A preformed roof ventilation system comprised of a panel including a middle section and flanged lateral edges. The middle section and flanged lateral edges forming a vent trough. The panel is installed on top of roof framing members prior to the addition of roof sheathing so that the flanged lateral edges can be secured between the roof framing members and the roof sheathing. The panel in combination with the roof sheathing creates a vent channel for channeling air from soffit vents along the underside of the roof sheathing and out of the attic through a ridge vent. The panel may further comprise a baffle flap with a living hinge that is adjustable to any pitched roof. The baffle flap forms a barrier to stop insulation from the attic from getting into the eave space and obstructing the soffit vents. Reinforcing elements and a formed grid pattern may be integrated along the length of the panels to increase the stiffness of each panel. Vent channel supports may also be integrated with the panel to aid in keeping the vent channel at a constant height after applying insulation. Additional panels can be added to extend the length of the vent channel.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 12/283,569, filed on Sep. 12, 2008, entitled “Self-Registering Roof Ventilation System”, which is incorporated herein by reference.

FIELD

This patent application relates generally to a roof ventilation system. In particular, the present patent application is directed to a roof ventilation system that incorporates an eave component and optional continuation components, each component for mounting between roof framing members and roof sheathing.

BACKGROUND

Residential and commercial buildings with sloped roofs typically include an open, unheated attic. The proper use of insulation and ventilation within the attic space can provide both energy conservation and help reduce common adverse conditions associated with moisture build up and extreme temperature variations. For example, during the summer extreme heat in the attic can degrade the roofing materials and increase cooling costs for the space below the attic. Insulation is normally placed in the ceiling/attic floor assembly to insulate the occupied levels of the building from the heat that builds up in the attic. A ventilation system is usually incorporated to reduce heat build-up and remove moisture from the attic. The ventilation system requires a combination of soffit vents that bring air into the attic and a ridge vent that allows air to vent out of the attic. In general, the air is moved along the underside of the roof sheathing by thermal convection. Where the soffit vents are located below the eaves of the roof, it is important to provide an air pathway between the soffit vent and the underside of the roof sheathing to allow for this air movement. This air pathway will allow cool air to enter through the soffit vent, run along the underside of the roof and exit through the ridge vent to cool the roof and allow moisture to escape. In cold climates, inadequate insulation and ventilation at the eaves often results in repeated freezing and thawing of snow which produces ice dams at the roof eaves. These dams can cause water to creep up under the shingles and leak into the building. Lack of ventilation will also cause moisture to condense on the underside of the roof and within the insulation. This moisture will degrade both the roof sheathing and reduce the effectiveness of the insulation. Prolonged moisture can also result in mold growth in the attic space. This condition can again be mitigated by providing a continuous and clear air pathway from the soffit vent along the underside of the roof to the ridge vent. Cool air entering from the soffit vent will flow through this pathway to cool the underside of the roof reducing snow melt higher up the roof that would then flow down the roof and freeze near the eaves creating an ice dam. The thermal convection of air will also remove airborne moisture that would otherwise condense on the underside of the roof or in the insulation.

It is therefore common in the building industry, and required by most building codes, to install some form of roof ventilation system that will provide a vent channel (air pathway) on the underside of the roof running from the eave space to an upper portion of the roof. It is also common to install some type of baffle that fits between roof framing members at the exterior wall plane to prevent insulation materials from getting into the eave space and thereby blocking the soffit vents. Most prior art roof ventilation baffles are designed to be installed after the roof has been completely sheathed with plywood or some other substrate. The process of installing and fitting “vent chutes” and baffles into the narrow, sloped areas where the eave portion of the roof intersects the exterior wall structure of the building can be tedious and time consuming. This process can lead to both ineffective vent formation and increased labor costs when constructing a building. It is apparent to those skilled in the art that opportunity exists for providing new and improved ventilation structures that can create an air passage between the soffit vents and the attic ridge vent. Such a structure should be one that is pre-formed, easy to align, does not have to be cut, and can adjust to any angle roof.

SUMMARY

One aspect of the present patent application is directed to a roof ventilation system comprising a panel that includes a middle section and flanged lateral edges. The middle section and flanged lateral edges creating a vent trough. At least one flanged lateral edge has a registration tab for registering with an adjacent panel. When the flanged lateral edges are secured between the top of roof framing members and the roof sheathing, a vent channel is created between the roof and the panel.

Another aspect is directed to a method of forming a roof vent channel comprising the steps of providing a framed roof with exposed roof framing members and a panel including a middle section and flanged lateral edges. The middle section and flanged lateral edges forming a vent trough. At least one of the flanged lateral edges has a registration tab for registering with an adjacent panel. The method then includes registering the panel to the adjacent panel on the roof framing members and securing the panel to the roof framing members. Roof sheathing is installed over the roof framing members and the panel to create the roof vent channel.

Yet another aspect is directed to a roof ventilation system for mounting between roof framing members and roof sheathing comprising a panel. The panel includes a roof side, an attic side, a first end and a second end. The panel further includes a vent trough formed from a first flanged lateral edge, a middle section and a second flanged lateral edge. The panel still further includes a reinforcing ventilation element spanning between the first and second flanged lateral edges, the reinforcing ventilation element containing at least one ventilation opening to allow moisture to travel between the roof side and attic side of the panel.

Still another aspect is directed to a roof ventilation system for mounting between roof framing members and roof sheathing comprising a panel. The panel includes a roof side, an attic side, a first end and a second end. The panel includes a vent trough formed from a first flanged lateral edge a middle section and a second flanged lateral edge, each flanged lateral edge having a canted section and a flat edge section extending outward parallel to the middle section. The panel further includes an array of vent channel supports dimensioned to extend from the middle section to a plane defined by the flat edge sections of the first and second flanged lateral edges. The panel still further includes a plurality of reinforcing elements spanning between and perpendicular to the first and second flanged lateral edges.

Still another aspect is directed to a roof ventilation system for mounting between roof framing members and roof sheathing comprising a panel. The panel includes a roof side, an attic side, a first end and a second end. The panel further includes a vent trough formed from a first flanged lateral edge, a middle section and a second flanged lateral edge, each flanged lateral edge having a canted section and a flat edge section extending outward parallel to the middle section. The panel still further including an array of vent channel supports dimensioned to extend from the middle section to a plane defined by the flat edge sections of the first and second flanged lateral edges, each vent channel support intersecting the plane a single apex.

Still yet another aspect is directed to an insulation dam for creating a barrier between attic space and eave space, the attic and eave space bounded by roof framing members and roof sheathing. The insulation dam comprises a flat and rectangular top panel having a top edge, a bottom edge, a first panel edge and second panel edge. The top panel has a width that spans greater than the width between the roof framing members. The insulation dam further comprise a baffle flap that has a top blocking edge and opposite framing edges. The blocking panel is attached at the top blocking edge by a hinge to the bottom edge of the top panel. The blocking panel spans the width of the roof framing members. Baffle flap tabs extend from each of the opposite frame edges of the baffle flap. Each baffle flap tab has a fold line where it meets each of the opposite frame edges. Whereby when the insulation dam is installed, each baffle flap tab bends toward the eave space and orients to attach substantially parallel to the inside of the roof framing members. A baffle flap gap exists between the top panel and each of the baffle flap tabs. The baffle flap tabs are dimensioned so that the baffle flap tabs do not stick into the plane of the roof sheathing when secured to the roof framing members.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other aspects and advantages of the invention will be apparent from the following detailed description as illustrated in the accompanying drawings, in which:

FIG. 1 a is a cut away, perspective view of one embodiment of the roof ventilation system showing eave components secured adjacent to each other on roof framing members with registration tabs aligned to registration gaps and a hinged baffle flap oriented to stop insulation from getting into the eave space;

FIG. 1 b is a sectional, partial cut away, side view of the roof ventilation system in FIG. 1 a, showing the baffle flap, the formation of the vent channel and how air flows from the soffit vent through the vent channel and out the ridge vent;

FIG. 2 is a perspective view of two eave components in FIG. 1 a, comprising panels laying adjacent to each other and secured to the roof framing members;

FIG. 3 is a sectional view perpendicular to roof framing members in FIG. 1 b, just interior the attic from the eave space showing the formation of the vent channel and its location relative to insulation;

FIG. 4 a is a perspective view of a first registration structure in accordance with the embodiments shown in FIGS. 1-22;

FIG. 4 b is a perspective view of a second registration structure in accordance with the embodiments shown in FIGS. 1-22;

FIG. 4 c is a perspective view of a third registration structure in accordance with the embodiments shown in FIGS. 1-22;

FIG. 4 d is a perspective view of a fourth registration structure in accordance with the embodiments shown in FIGS. 1-22;

FIG. 4 e is a perspective view of a fifth registration structure in accordance with the embodiments shown in FIGS. 1-22;

FIG. 5 is a perspective view showing key features of the eave component of FIGS. 1 a, 1 b and 2, and how multiple eave components may be compactly stacked for shipping;

FIG. 6 a is a perspective view showing how the incorporation of a living hinge as part of the eave component of FIGS. 1 a, 1 b and 2, and how this living hinge allows the user to adjust the baffle flap for any slope roof;

FIG. 6 b is a perspective view showing the structure of a living hinge for panels shown in FIGS. 1-2, 5, 6 a, 9 a-11, 15, 17 a, 18 a, 18 b and 22-24;

FIG. 6 c is a perspective view of the living hinge of FIG. 6 b with the baffle flap now angled to fit the slope of a roof;

FIG. 7 is a perspective view showing key features of a continuation component that would be used as shown in FIGS. 9 a, 9 b and 10;

FIG. 8 is a perspective view of the continuation component of FIG. 7, but now with perforations that allow for additional ventilation of insulation;

FIG. 9 a is a perspective view showing the use of the eave components of FIG. 5 and the continuation components of FIG. 7 when the building has a cathedral ceiling;

FIG. 9 b is a perspective view showing the use of the eave components of FIG. 5 and the continuation components of FIG. 7 when the building has a finished attic;

FIG. 10 is a perspective view showing how a continuation component of FIG. 7 may be installed in a framing bay in conjunction with an eave component of FIG. 5 to extend the length of a vent channel;

FIG. 11 is a perspective view showing how a user can hold the eave components of FIG. 5 and continuation components of FIG. 7 during installation of the self-registering roof ventilation system;

FIG. 12 a is a perspective view of a portion of a panel in one embodiment showing a first structure of an integral reinforcing ventilation element integrated with a panel, the panel may be that of an eave component or a continuation component;

FIG. 12 b is a perspective view of a portion of a panel in one embodiment showing a second structure of an integral reinforcing ventilation element integrated with a panel, the panel may be that of an eave component or a continuation component;

FIG. 12 c is a perspective view of a portion of a panel in one embodiment showing a third structure of an integral reinforcing ventilation element integrated with a panel, the panel may be that of an eave component or a continuation component;

FIG. 13 a is a perspective view of one embodiment showing a mountable reinforcing ventilation element;

FIG. 13 b is a sectional view along line A-A of FIG. 13 a showing the cross-sectional shape of the mountable reinforcing ventilation element;

FIG. 14 a is an exploded, perspective view of a portion of a panel showing how the mountable reinforcing ventilation element of FIGS. 13 a and 13 b is mounted over a ventilation slot in the panel;

FIG. 14 b is a sectional view along line B-B of FIG. 14 a showing how when the mountable reinforcing ventilation element is mounted moisture can move from the attic side to the eave side of the panel;

FIG. 15 is a perspective view showing how the reinforcing ventilation elements depicted in FIGS. 12-14 maybe added and spaced along the length of an eave component of FIG. 5;

FIG. 16 is a perspective view showing how the reinforcing ventilation elements depicted in FIGS. 12-14 may be added and spaced along the length of an extension component of FIG. 7;

FIG. 17 a is a perspective view showing key features of a reinforced eave component in FIG. 15 and how multiple eave components may be compactly stacked for shipping;

FIG. 17 b is a perspective view along line C-C of FIG. 17 a showing how mountable reinforcing ventilation elements fit within each other for compact stacking;

FIG. 18 a is a perspective view of one embodiment of the eave component where the panel includes reinforcing elements, vent channel supports, a formed grid pattern and interlocking elements;

FIG. 18 b is a perspective view of the eave component in FIG. 18 a, further including registration tabs and registration gaps;

FIG. 19 a is a perspective view of one embodiment of the continuation component where the panel includes reinforcing elements, vent channel supports, a formed grid pattern and interlocking elements;

FIG. 19 b is a perspective view of the continuation component in FIG. 19 a, further including registration tabs and registration gaps;

FIG. 20 a is a perspective view of a portion of the panel in FIGS. 18 a-19 b, showing key features of the reinforcing element and vent channel support;

FIG. 20 b is a perspective view of a portion of the panel in FIGS. 18 a-19 b, showing details of the vent channel supports, and the formed grid pattern within the middle section and canted sections;

FIG. 20 c is a perspective view of a portion of the panel in FIGS. 18 a-19 b, showing key features of the interlocking element;

FIG. 21 a is a sectional view perpendicular to roof framing members for an eave component of FIG. 18 a after installation, the section through a reinforcing element just interior the attic from the eave space showing the formation of the vent channel and its location relative to insulation;

FIG. 21 b is a sectional view perpendicular to roof framing members for an eave component of FIG. 18 a after installation, the section through a vent channel supports just interior the attic from the eave space showing the formation of the vent channel and its location relative to insulation;

FIG. 21 c is a sectional view perpendicular to roof framing members for an eave component of FIG. 18 a after installation, the section through a interlocking component interior the attic showing the formation of the vent channel and its location relative to insulation;

FIG. 22 is a perspective view showing how a continuation component of FIG. 19 a may be installed in a framing bay in conjunction with an eave component of FIG. 18 a to extend the length of a vent channel;

FIG. 23 a is a cut away, perspective view of one embodiment of a roof ventilation system showing insulation dams secured adjacent to each other on roof framing members and a hinged baffle flap oriented to stop insulation from getting into the eave space;

FIG. 23 b is a front, perspective view showing the insulation dam of FIG. 23 a installed in a framing bay; and

FIG. 24 is a perspective view showing key features of the insulation dam of FIGS. 23 a and 23 b, and how multiple eave components may be compactly stacked for shipping.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-22 illustrate the elements of roof ventilation system 20. Roof ventilation system 20 is designed to be installed in new or renovated buildings on top of exposed roof framing members 22 prior to the installation of roof sheathing 24. Roof ventilation system 20 comprises one or more eave components 21 and optional continuation components 23 depending on the application. Eave component 21 comprises a panel 26 including flanged lateral edges 28 a (a.k.a. first flanged lateral edge) and 28 b (a.k.a. second flanged lateral edge). Panel 26 also includes a first end 30 and a second end 32, and a panel length between the first and second ends. Panels 26 are preferably rectangular. Panels 26 are nominally 16-inches or 24-inches wide to fit over roof framing members 22. Roof framing members 22 are usually spaced at 16-inches and 24-inches on center. Depending on the application, panels 26 have a panel length that may range from 30-inches to 60-inches. The panels may range in thickness from 0.010-inches to 0.080-inches. Flanged lateral edges 28 a and 28 b protrude upward and outward from a substantially flat middle section 34 of panel 26. Together first flanged lateral edge 28 a, middle section 34 and second flanged lateral edge 28 b form vent trough 35, with the length of the vent trough extending between first end 30 and second end 32 of panel 26. Flanged lateral edges 28 a and 28 b provide a way to secure panel 26 to roof framing members 22. When in place, the space between the top side of the middle section 34 and bottom side of roof sheathing 24 will create a continuous vent channel 36 preferably 1.5-inches to 2-inches in depth, FIGS. 3 and 21 a-21 c. Although preferably flat, middle section 34 of panel 26 may take on any shape that creates an appropriate vent channel 36. This may include, but is not limited to cross-sections that are arcuate, channeled and ridged. Middle section 34 may also have a formed grid pattern to increase the stiffness of panel 26. The canted section 38 of each flange allows for easy positioning and provides for compression/tension adjustment of panel 26 between pairs of roof framing members 22. Canted sections 38 also define the side walls of vent channel 36. Canted sections 38 are sized to generally provide 1.5-inches to 2-inches of generally unobstructed space between the underside of roof sheathing 24 and the top side of middle section 34. This sizing allows for clear air flow and avoids the ends of roofing nails 40 used during roofing to damage panel 26. Vent channel 36 runs the full width of framing bay 41 bounded by roof framing members 22. This provides ventilation to nearly 100% of the underside of roof sheathing 24 versus only a portion of the sheathing as most other prior art does. The generally flat portion of flanged lateral edges 28 a and 28 b that extends outward from canted sections 38 and runs along the length of panel 26 is defined as edge section 42. Canted section 38 may be at one angle or continuously change angle from middle section 34 to edge section 42. The bottom side of edge section 42 is designed for resting on top of roof framing members 22 when installed.

In several embodiments, FIGS. 1 a, 2-12,14-17, 18 b and 19 b, edge section 42 may incorporate or be divided into one or more registration tabs 44 or registration gaps 46. However for other embodiments, FIGS. 18 b and 19 b-22, registration tabs 44 and registration gaps 46 are not present and edge section 42 is a continuous flat edge section along the length of panel 26. Edge section 42 may also extend to rest completely over the top of a roof framing member 22 and extend to go down the other side of the roof framing member in sort of a hooked fashion, FIG. 4 d. Edge section 42 is the preferred section of panel 26 through which to secure the panels to roof framing members 22. Panels 26 may be secured by nails, screws, staples or other fasteners 43. A portion of edge section 42 in embodiments with registration tabs 44 and registration gaps 46 is defined as stiffening rim 45 and is ¼^(th) to ½-inch wide. Stiffening rim 45 is continuous (uninterrupted by registration gaps 46) along the length of the panel and adjacent to canted sections 38. Stiffening rim 45 provides added rigidity to the edges of panel 26. A continuous stiffening rim 45 is shown in FIGS. 4 a, 4 b and 4 e. Other portions of panel 26, such as canted sections 38, may be used to secure the panel to roof framing members 22 without deviating from the scope of the invention.

FIGS. 4 a-e show several different registration structures for registration tab 44 for those embodiments where flanged lateral edge 28 a and 28 b of eave component 21 have at least one registration tab for alignment to an adjacent panel. When installed each registration tab 44 preferably aligns within a registration gap 46 of an adjacent panel. It is preferable to have a plurality of registration tabs 44 and registration gaps 46 on each flanged lateral edge 28 a and 28 b of panel 26. It is also preferable to have a series of alternating registration tabs 44 and registration gaps 46 on each flanged lateral edge 28 a and 28 b that have widths that are approximately equal, but preferably less than the full width of edge section 42. For a given location along the length of panel 26 running from first end 30 to second end 32, the first flanged lateral edge 28 a will have a registration tab 44 and the second flanged lateral edge 28 b will have a corresponding registration gap 46. Further along the length of panel 26 the first flanged lateral edge 28 a will then have a registration gap 46 and the second flanged lateral edge 28 b will then have a registration tab 44. This structure allows a plurality of panels 26 to be laid side-by-side upon roof framing members 22 adjacent to each other and have the panels self-register with registration tab 44 in corresponding registration gap 46. It is also preferable to have registration tabs 44 and registration gaps 46 of relatively equal length with the gaps equal to or larger than the tabs so that the tabs fit within the gaps to help aid with registration of adjacent panels and provide tight alignment tolerances. Overall, registration tab 44 and registration gap 46 alignment tolerances should be 0.25-inches or less. For example, registration tabs 44 are preferably 5⅞ inches long, 1⅛ inches wide within an edge section 42 having a width of 1½ inches. Registration gaps 46 are preferably 6⅛ inches long, 1⅛ inches wide within an edge section 42 having a width of 1½ inches.

Eave component 21 further includes a baffle flap 48 on first end 30 of panel 26. Baffle flap 48 is preferably 13½ inches long, but the baffle flap may take any length appropriate for the exact application. Baffle flap 48 is integrated with panel 26 by way of a living hinge 50. Panel 26 and baffle flap 48 are preferably fabricated as one integral unit during manufacture. Baffle flap 48 is adjusted down during installation to create a barrier between attic space 52 and eave space 54. The purpose of baffle flap 48 is to keep insulation 56, which may be laid or blown between ceiling framing members 58, from getting into eave space 54. Baffle flap 48 has two baffle flap tabs 60 a and 60 b that are formed from the canted sections 38. Baffle flap tabs 60 a and 60 b are secured by fasteners 43 such as nails, screws and staples to the sides of roof framing members 22 as shown in FIGS. 2, 10 and 22.

Baffle flap 48 can adjust for any slope roof by way of living hinge 50, FIG. 6 a. Living hinge 50 is formed as a thinned region at the first end of panel 26. This thinned region is created during the manufacture of panels 26 by a press with a blunt heated blade, contact with a hot wire, partial milling or other means similar thinning means. A close-up view of the structure of living hinge 50 is shown in FIGS. 6 b and 6 c. Living hinge 50 extends continuously across the width of middle section 34 of panel 26 at first end 30. Where middle section 34 meets canted section 38, living hinge 50 terminates as a gap in the canted sections of both flanged lateral edges 28 a and 28 b. Living hinge 50 is not a perforated fold line or line that needs to be scored as is the case in the prior art. Fold lines are subject to creasing and generate poorly formed folds. Score lines are subject to the user improperly scoring the baffle and having the baffle not fold uniformly where needed.

In one embodiment, FIGS. 1 a, 5, 9 a, 9 b, 10, 11, 15 and 17 a, eave component 21 may further include one or more extension openings 60 near second edge 32 of panel 26. Extension openings 60 may be a gap, a slot or other appropriately shaped opening. Extension opening 60 may be positioned adjacent to or just interior second end 32. The primary function of extension opening 60 is to accept an interlocking tab 62 from continuation component 23, FIG. 10. Extension opening 60 also functions to help with self-registering continuation component 23 to eave component 21 using interlocking tabs 62. Furthermore, extension opening 60 may function as a convenient way to carry or hold eave component 21 during installation, FIG. 11.

Continuation component 23 is for extending the length of vent trough 35 and resulting vent channel 36 in certain applications. Continuation component 23, shown in FIGS. 7-10, 16, 19 a, 19 b and 22, comprises a panel 26 including flanged lateral edges 28 a (a.k.a. first flanged lateral edge) and 28 b (a.k.a. second flanged lateral edge). Panel 26 also includes a first end 30 and a second end 32 that respectively define the first end and second ends of continuation component 23. Panels 26 are preferably rectangular. Panels 26 are nominally 16-inches or 24-inches wide to fit over roof framing members 22. Roof framing members 22 are usually spaced at 16-inches and 24-inches on center. Depending on the application, panels 26 have a panel length that may range from 30-inches to 60-inches. The panels may range in thickness from 0.010-inches to 0.080-inches. Flanged lateral edges 28 a and 28 b protrude upward and outward from a substantially flat middle section 34 of panel 26. Together first flanged lateral edge 28 a, middle section 34 and second flanged lateral edge 28 b form vent trough 35, with the length of the vent trough extending between first end 30 and second end 32 of panel 26. Flanged lateral edges 28 a and 28 b provide a way to secure panel 26 to roof framing members 22. When in place, the space between the top side of the middle section 34 and bottom side of roof sheathing 24 will create a continuous vent channel 36 preferably 1.5-inches to 2-inches in depth. Although preferably flat, middle section 34 of panel 26 may take on any shape that creates an appropriate vent channel 36. This may include, but is not limited to cross-sections that are arcuate, channeled and ridged. Middle section 34 may also have a formed grid pattern to increase the stiffness of panel 26. The canted section 38 of each flange allows for easy positioning and provides for compression/tension adjustment of panel 26 between pairs of roof framing members 22. Canted sections 38 also define the side walls of vent channel 36. Canted sections 38 are sized to generally provide 1.5-inches to 2-inches of unobstructed space between the underside of roof sheathing 24 and the top side of middle section 34. This sizing allows for clear air flow and avoids the ends of roofing nails 40 used during roofing to damage panel 26. Vent channel 36 runs the full width of framing bay 41 bounded by roof framing members 22. This provides ventilation to nearly 100% of the underside of roof sheathing 24 versus only a portion of the sheathing as most other prior art does. The generally flat portion of flanged lateral edges 28 a and 28 b that extends outward from canted sections 38 and runs along the length of panel 26 is defined as edge section 42. Canted section 38 may be at one angle or continuously change angle from middle section 34 to edge section 42. The bottom side of edge section 42 is designed for resting on top of roof framing members 22 when installed.

In several embodiments, FIGS. 7-10, 16 and 19 b, edge section 42 of eave component 23 may incorporate or be divided into one or more registration tabs 44 or registration gaps 46. However for other embodiments, FIGS. 19 a, 20 a-22, registration tabs 44 and registration gaps 46 are not present and edge section 42 is a continuous flat edge section along the length of panel 26. Edge section 42 may also extend to rest completely over the top of a roof framing member 22 and extend to go down the other side of the roof framing member in sort of a hooked fashion, FIG. 4 d. Edge section 42 is the preferred section of panel 26 through which to secure the panels to roof framing members 22. Panels 26 may be secured by nails, screws, staples or other fasteners 43. A portion of edge section 42 in embodiments with registration tabs 44 and registration gaps 46 is defined as stiffening rim 45 and is ¼^(th) to ½-inch wide. Stiffening rim 45 is continuous (uninterrupted by registration gaps 46) along the length of the panel and adjacent to canted sections 38. Stiffening rim 45 provides added rigidity to the edges of panel 26. A continuous stiffening rim 45 is shown in FIGS. 4 a, 4 b and 4 e. Other portions of panel 26, such as canted sections 38, may be used to secure the panel to roof framing members 22 without deviating from the scope of the invention.

FIGS. 4 a-e show several different registration structures for registration tab 44 for those embodiments where flanged lateral edge 28 a and 28 b of continuation component 23 have at least one tab for alignment to an adjacent panel. When installed each registration tab 44 preferably aligns within a registration gap 46 of an adjacent panel. It is preferable to have a plurality of registration tabs 44 and registration gaps 46 on each flanged lateral edge 28 a and 28 b of panel 26. It is also preferable to have a series of alternating registration tabs 44 and registration gaps 46 on each flanged lateral edge 28 a and 28 b that have widths that are approximately equal, but preferably less than the full width of edge section 42. For a given location along the length of panel 26 running from first end 30 to second end 32, the first flanged lateral edge 28 a will have a registration tab 44 and the second flanged lateral edge 28 b will have a corresponding registration gap 46. Further along the length of panel 26 the first flanged lateral edge 28 a will then have a registration gap 46 and the second flanged lateral edge 28 b will then have a registration tab 44. This structure allows a plurality of panels 26 to be laid side-by-side upon roof framing members 22 adjacent to each other and have the panels self-register with registration tab 44 in corresponding registration gap 46. It is also preferable to have registration tabs 44 and registration gaps 46 of relatively equal length with the gaps equal to or larger than the tabs so that the tabs fit within the gaps to help aid with registration of adjacent panels and provide tight alignment tolerances. Overall, registration tab 44 and registration gap 46 alignment tolerances should be 0.25-inches or less. For example, registration tabs 44 are preferably 5⅞ inches long, 1⅛ inches wide within an edge section 42 having a width of 1½ inches. Registration gaps 46 are preferably 6⅛ inches long, 1⅛ inches wide within an edge section 42 having a width of 1½ inches.

In one embodiment, FIGS. 7-10, continuation component 23 may further include at least one interlocking tab 62 at first end 30 for interlocking with a second continuation component 23 or an eave component 21. Continuation component 23 may further include one or more extension openings 60. Extension openings 60 may be a gap, a slot or other appropriately shaped opening. Extension opening 60 may be placed adjacent to or just interior second end 32 of panel 26. The primary function of extension opening 60 is to accept an interlocking tab 62 from a second continuation component 23. Extension opening 60 also functions to help with self-registering a first continuation component 23 to a second continuation component 23. Furthermore, extension opening 60 may function as a way to conveniently carry or hold continuation components 23 during installation.

Eave components 21 and continuation components 23 can both be fabricated using several methods. These methods include, but are not limited to stamping, extrusion, vacuum forming, pressure forming, thermal molding and injection molding. The preferred fabrication material is a plastic such as PVC, ABS, HDPE, LDPE, polystyrene or other plastic compound. However, non-plastics such as corrugated cardboard, thin metal sheets and other composite materials may be used. Cost, weight, strength, structural rigidity over the expected environmental temperature range and fabrication costs all determine which material is appropriate for a given application. Since each type of component (eave component 21 or continuation component 23) is substantially flat and each type has the same shape, components of the same type can be easily stacked and packaged in groups of ten to twenty-four units at a time as shown in FIGS. 5 and 17 a. These packages can then be easily shipped to the work site.

In one embodiment eave component 21 and continuation component 23 may include perforations 64 as shown in FIG. 8. Perforations 64 provide a way for moisture to escape from insulation 56, enter vent channel 36 and be carried away by the flowing air. Spray foam insulation having a closed cell structure requires no perforations 64; while fiberglass, cellulose and open cell spray foam may require the perforations. Perforations 64 may range in diameter from 1/16-inch to ½-inch and the perforations are spaced from 1-inch to 3-inches apart depending on the application.

In one embodiment panels 26 of eave component 21 or continuation component 23 may include reinforcing ventilation elements 100, FIGS. 12 a-17 b. Reinforcing ventilation element 100 comprises a stiffening element 102 (a.k.a. reinforcing element 160) and a ventilation element 104. Reinforcing ventilation element 100 spans between first lateral edge 28 a and second lateral edge 28 b and is oriented substantially perpendicular to the first lateral edge and second lateral edge. A plurality of reinforcing ventilation elements may be spaced along the length of panel 26 to achieve the desired ventilation and stiffening. Stiffening element 102 includes at least one raised wall 106 that extend upward from middle section 34, but preferably two parallel raised walls creating an elongated structure. Walls 106 preferably are oriented substantially perpendicular to attic side 122 and roof side 124 of panel 26, but may be at an angle to middle section 34. Walls 106 provide stiffness to the panel. The amount of stiffness is proportional to the height of the walls. Ventilation element 104 includes ventilation openings 108. There are two embodiments for reinforcing ventilation elements 100, integral reinforcing ventilation elements 100 a and mountable reinforcing ventilation elements 100 b.

FIGS. 12 a-c show three structures for integral reinforcing ventilation element 100 a. Integral reinforcing ventilation element 100 a is formed from middle section 34 of panel 26. Integral reinforcing ventilation element 100 a may be formed by injection molding or thermoforming. In a first structure, FIG. 12 a, stiffening walls 106 of stiffening element 102 rise from middle section 34 of panel 26. Stiffening walls 106 span between flanged lateral edges 28 and are substantially perpendicular to the flanged lateral edges. Together top region 110 and stiffening walls 106 form a raised stiffening element 102. Ventilation openings 108 are shown in walls 106. In a second structure, FIG. 12 b, ventilation openings 108 may be in top region 110. Other variations of integral reinforcing ventilation element 100 a may include an arched versus rectangular cross-section. In such a structure, arched stiffening walls 106 combined together with ventilation openings 108 generate reinforcement ventilation element 100 a. In a third structure, FIG. 12 c, ventilation ledge 114 may be a separate element that surrounds stiffening element 102. Vent ledge 114 has a substantially vertical ledge wall 119 and top shelf 120 creating the ledge. Ventilation openings 108 may exist in vertical ledge wall 119, top shelf 120 or both.

FIGS. 13 a and 13 b show a structure for a mountable reinforcing ventilation element 100 b. Mountable reinforcing ventilation element 100 b is preferably thermally formed from a piece of plastic such as PVC, ABS, HDPE, LDPE, polystyrene or other plastic compound. In this preferred embodiment, mounted reinforcing ventilation element 100 b comprises a peripheral sealing edge 118, a vent ledge 114 and a stiffening element 102. Peripheral sealing edge 118 is for mounting to middle section 34 of panel 26. Mountable reinforcing ventilation element 100 b is an elongated element that is mounted substantially perpendicular to flanged lateral edges. Mounted reinforcing ventilation element 100 b may be adhesively mounted with an adhesive 120 that is applied to a portion or the whole sealing edge. Mounted reinforcing ventilation element 100 b may also be glued, fastened with fasteners or thermally bonded to panel 26. Vent ledge 114 has a substantially vertical ledge wall 119 and top shelf 120 creating the ledge. Ventilation openings 108 are cut from peripheral sealing edge 118 into vent ledge 114. Stiffening element 102 includes at least one raised wall 106 that extends upward from middle section 34, but preferably two parallel raised walls creating an elongated structure. Together top region 110 and stiffening walls 106 form raised stiffening element 102. Stiffening element 102 is preferably interior the vent ledge 114 and has stiffening walls 106 that extend substantially perpendicular to the roof side of panel 26 to provide stiffness. The amount of stiffness provided to panel 26 is proportional to the height of the stiffening walls 106 and the ledge walls 122.

FIGS. 14 a and 14 b show how mountable reinforcing ventilation element 100 b is mounted to panel 26 and how when in place it works to allow moisture to pass from attic side 122 to roof side 124 of the panel. Mountable reinforcing ventilation element 100 b is mounted over a ventilation slot 126 in panel 26 by adhesive 120. Ventilation slot 126 in combination with mountable reinforcing ventilation element 100 b limit the amount of insulation 56 that can pass from attic side 122 to roof side 124, however, the structure allows moisture 128 to pass from the attic side to the roof side and escape up vent channel 36 and out ridge vent 82.

FIGS. 15 and 16 show eave component 21 and continuation components 23 having reinforcing ventilation elements 100 spaced along the length of each panel 26. Reinforcing ventilation elements may be integral reinforcing ventilation elements 100 a or mountable reinforcing elements 100 b.

In the case of mountable reinforcing ventilation elements 100 b, ventilation slot 126 also provides an important function for stacking eave components 21 or continuation components 23, FIGS. 17 a and 17 b. Ventilation slot 126 allows stiffening element 102 to pass through a panel 26 placed on top of it and therefore allow for more compact stacking and shipping of components. If integral reinforcing elements are used, a similar recess will exist on attic side 122 of panel 26, again allowing for more compact stacking and shipping of components.

In one embodiment panels 26 of eave component 21 or continuation component 23 may include reinforcing elements 160 (a.k.a. stiffening element 102), FIGS. 18 a-20 a, 20 c, 21 a, 21 c and 22. Reinforcing element 160 spans between first lateral edge 28 a and second lateral edge 28 b and is oriented substantially perpendicular to the first lateral edge and second lateral edge. Reinforcing elements 160 may have saddles 162 for added strength. A plurality of reinforcing elements 160 may be spaced along the length of panel 26 to achieve the desired stiffening. Reinforcing element 160 includes at least one raised wall 106 that extend upward from middle section 34, but preferably two parallel raised walls creating an elongated structure. Walls 106 preferably are oriented substantially perpendicular to attic side 122 and roof side 124 of panel 26, but may be at an angle to middle section 34. Walls 106 provide stiffness to the panel. The amount of stiffness is proportional to the height of the walls.

In one embodiment panels 26 of eave component 21 or continuation component 23 may include vent channel supports 170, FIGS. 18 a-22. Vent channel supports 170 are dimensioned to extend from middle section 34 to a plane 172 defined by flat edge section 42 of first lateral edge 28 a and second lateral edge 28 b, FIG. 21 a-21 c. Each vent channel support 170 intersects plane 172 at a single apex 174. Vent channel supports 170 are surrounded on all sides by a portion of middle section 34 making them discrete locations of support. Vent channel supports 170 include but are not limited to structures such as domes, cones and pyramids. Vent channel supports 170 may be of different sizes depending on their location within middle section 34, but always have a height that allows their single apex 174 to intersect at plane 172. Gussets 176 may be integrated on the edges of vent channel supports 170 to provide further stiffness. It is preferable to have an array of vent channel supports positioned over the area of middle section 34. Vent channel supports 170 provide a unique way of supporting a relatively thin panel from collapsing into vent channel 36 when insulation is sprayed, blown or pressed in from attic side 122 of panel 26. When installed each vent channel support 170 provides a single point of minimal contact with roof sheathing 24 at apex 174. The array of single points of contact provides for close to 100% ventilation of the exposed underside of roof sheathing 24.

In one embodiment panels 26 of eave component 21 or continuation component 23 may further include a formed grid pattern 180, FIGS. 18 a-22. Formed grid pattern 180 is a series of ridges and troughs imprinted within an area of a generally uniform thickness sheet. This formed grid pattern is used to strengthen a relatively thin flat section of panel such as middle section 34 and canted sections 38 of panel 26. This pattern is critical for integrity of the panel for certain materials such as PVC in the thickness range of 0.010-inches to 0.030-inches. Manufacturing the panels from thinner material helps reduce materials costs. Therefore the addition of a formed grid pattern 180 allows for the use of thinner materials and decreases the cost to fabricate the panels.

In one embodiment panels 26 of eave component 21 or continuation component 23 may further include interlocking elements 190 (190 a and 190 b), first interlocking element 190 a at first end 30 and second interlocking element 190 b at second end 32, FIGS. 18 a-19 b, 20 c, 21 c and 22. These types of interlocking elements can be used instead of the interlocking tabs 26 and extension openings 60. They provide the ability to add continuation components 23 along the length of roof framing members 22 to extend the length of vent trough 35. First interlocking element 190 a fits over and interlocks with second interlocking element 190 b. Interlocking elements 190 may include one or more vent channel supports 170 and a reinforcing element 160. By having the first end 30 of each continuation component 23 shingle-lapped over other components already in place, a secondary rain barrier is created below roof sheathing.

Eave components 21 and continuation components 23 of roof ventilation system 20 are designed to be installed on top of exposed roof framing members 22 just prior to applying roof sheathing 24. This installation can occur in new building construction or when a roof structure is being renovated. The overall roof structure at installation is similar to that shown in FIGS. 1 a, 9 a and 9 b. Although the embodiment of eave components 21 and expansion components 23 without reinforcing elements and with registration tabs and gaps is shown, any of the embodiments disclosed could be installed in a similar manner. Installation occurs without roof sheathing 24 and without roofing 66 in place. The roof structure comprises roof framing members 22 typically spaced at 16-inches or 24-inches on center. Ceiling framing members 58 are secured to roof framing members 22 and wall top plate 68. Ceiling 70 is secured to the bottom of ceiling framing members 58. The slope of roof framing members 22 may be any slope as defined by the building design. Where roof framing members 22 overhang the edge of the building they create eave 72. Eave 72, facia 74, soffit 76 and exterior wall 78 of the building create eave space 54. Soffit vents 80 are provided continuously or at intervals along soffit 76 as fresh air 77 intakes. As shown in FIG. 2, a first panel 26 a (in this case an eave component) is laid on roof framing members 22 and living hinge 50 is aligned with the face of exterior wall 78. Baffle flap 48 overlaps top plate 68 of the exterior wall 78 of the building. Top plate 68 and exterior wall 78 may or may not be covered with plywood 79. If the panel has registration tabs 44, then the registration tabs are fastened to the top of roof framing members 22 as required to hold in place, using fasteners 43, for example staples. Baffle flap tabs 60 a and 60 b are then secured to roof framing members 22 by appropriate fasteners 43, again for example staples. A second panel 26 b is then laid adjacent to first panel 26 a between the next two adjacent roof framing members 22. Registration tabs 44 of second panel 26 b are then placed within and registered to corresponding registration gaps 46 of first panel 26 a. First panel 26 a and second panel 26 b are now self-registered. The result of registering first panel 26 a to second panel 26 b causes the two panels to be aligned to each other. If the panels do not have the feature of registration tabs and registration gaps, but instead a continuous edge section 42 as shown in FIGS. 18 a, 19 a and 20 a-22, then the panels are just laid with the continuous edge sections next to or on top of each other. Baffle flap 48 of second panel 26 b is then adjusted and secured to roof framing members 22. This process continues with successive panels until the entire eave side of the roof structure is fitted with eave components. Once the eave components are in place, roof sheathing 24 and roofing 66 are installed over roof framing members 22 and panels 26, FIGS. 1 a, 3, 9 a, 9 b and 21 a-21 c. This process completes the formation of vent channels 36. Insulation 56 can then be blown, sprayed or laid around the edges of attic space 52 without worry of the insulation getting into eave space 54 and clogging soffit vents 80. Once roof ventilation system 20 is complete, fresh air 77 enters through soffit vents 80, flows through channel vent 36 and exits through ridge vent 82, FIG. 1 b.

In certain applications such as cathedral ceilings 84 (FIG. 9 a) or finished attics 86 (FIG. 9 b) eave components 21 may require the use of continuation components 23 to extend the length of vent channel 36. FIGS. 10 and 22 show for a single framing bay 41 how continuation component 23 may be added to eave component 21. Because each component comprises a panel 26, this structure includes a first panel added adjacent to a second panel along the length of roof framing members 22. In FIG. 10 interlocking tabs 62 of continuation component 23 fit within extension openings 60 of eave component 21. Interlocking tabs 62 help register the two components in place. In FIG. 22 first interlocking element 190 a of continuation component 23 fits over the interlocking element 190 b of eave component 21. Additional continuation components 23 can be added in a similar manner to the structure to continue the extension of vent channel 36 as required. In some cases where eave component 21 and continuation component 23 do not have ventilation mechanisms built in to the panels, the panels could be extended by having a small ½-inch to 2-inch space between the ends of each panel to aid in ventilation. This would be the case for some types of batt insulations such as fiberglass and rock wool are used.

As shown in FIG. 11, if panel 26 has extension openings 60 at the second end 32 of the panels 26 a complete installation system 88 for installing roof ventilation system 20 is created. Extension openings 60 can be used as a method of holding panels 26 by a panel hanger 90 while they are being installed by the worker 92.

The embodiments disclosed in this application provide a simple and inexpensive way to create a roof ventilation system with air pathways along the bottom side of a roof. The ventilation system is efficient and easy to install. Furthermore, the ventilation system can be used in numerous roof ventilation applications by incorporating multiple components comprising panels that register and interlock together.

If ventilation channels are not required as part of the roof formation and insulation process (i.e., a non-vented roof), an alternative to the above disclosed eave and continuation components may be used. This is usually the situation for when open or closed cell spray foam or dense pack fiber insulation is used. This alternative component, an insulation dam 130, is used to create a barrier between attic space 52 and eave space 54, FIGS. 23 a and 23 b. Insulation dam 130 comprises a generally flat and rectangular top panel 132. Top panel 132 includes a top edge 134, a bottom edge 136, a first top panel edge 138 and a second top panel edge 140. Top panel 132 has a width that is greater than the width between roof framing members 22. However, it is preferable to have the width of top panel 132 equal to or less than the combination of the width between roof framing members 22 and the width of the two framing members. First top panel edge 138 and second top panel edge 140 of top panel 132 are for mounting between roof framing members 22 and roof sheathing 24. First top panel edge 138 and second top panel edge 140 are preferably mounted on top of roof framing members 58. Roof sheathing 24 may include one or more layers such as wood sheathing 142 (plywood, OSB) and an underlayment weather protecting membrane 144 such as TYVEK® or other similar product. Attached to bottom edge 136 of top panel 132 is a baffle flap 48 a having a top blocking edge 150, a bottom blocking edge 152 and opposite framing edges 154 a and 154 b. Baffle flap 48 a spans the width between roof framing members 22. Top panel 132 and baffle flap 48 a are integrated by way of a living hinge 50 a between bottom edge 146 and top blocking edge 150. Baffle flap 48 a is adjusted down during installation to create a barrier between attic space 52 and eave space 54. The purpose of baffle flap 48 a is to keep insulation 56, from getting into eave space 54. Baffle flap 48 a has two baffle flap tabs 60 c and 60 d that extend from opposite framing edges 154 a and 154 b of the baffle flap. Baffle flap tabs 60 c and 60 d are preferably rectangular baffle flap tabs. Baffle flap tabs 60 c and 60 d are created from the same material as baffle flap 48 a, but have fold line 160 created by a score or crease at opposite framing edges 154 a and 154 b of the baffle flap, this allows the tabs to bent to extend towards eave space 54 when installed. When installed, baffle flaps tabs 60 c and 60 d are oriented to attach substantially parallel to the inside of roof framing members 22. Insulation dam 130 further comprises a baffle flap gap 156 between top panel 132 and each baffle flap tab 60 c and 60 d. Baffle flap gap 156 is dimensioned so that baffle flap tabs 60 c and 60 d do not stick into the plane of roof sheathing 24 when secured to the inside of roof framing members 22. Top panel 132, baffle flap 48 a and baffle flap tabs 60 c and 60 d are preferably fabricated as one integral unit during manufacture. Insulation dams 130 may be stacked flat in groups of forty to one hundred for shipping as shown in FIG. 24.

The self-registering roof ventilation system described above is not limited to the embodiments represented but includes all variants notably those concerning the materials used to form the eave components, the continuation components and the insulation dams, the exact shape and spacing of registration tabs and gaps, the exact type and shape of elements to interlock eave and continuation components, the size and shape of any vent channel supports and the cross-sectional shape used to form vent channels. Nothing in the above specification is intended to limit the invention more narrowly than the appended claims. The examples given are intended only to be illustrative rather than exclusive. 

1) A roof ventilation system for mounting between roof framing members and roof sheathing, comprising: a panel including: a) a roof side, an attic side, a first end and a second end; b) a vent trough formed from a first flanged lateral edge, a middle section and a second flanged lateral edge, wherein each said flanged lateral edge has a canted section, wherein each flanged lateral edge has a flat edge section extending outward parallel to said middle section; c) an array of vent channel supports dimensioned to extend from said middle section to a plane defined by said flat edge sections of said first and second flanged lateral edges; and d) a plurality of reinforcing elements spanning between and perpendicular to said first and second flanged lateral edges. 2) A roof ventilation system as recited in claim 1, wherein each vent channel support is surrounded on all sides by said middle section. 3) A roof ventilation system as recited in claim 1, wherein said middle section includes a formed grid pattern. 4) A roof ventilation system as recited in claim 1, wherein said canted sections of said flanged lateral edges includes a formed grid pattern. 5) A roof ventilation system as recited in claim 1, wherein said panel further includes a registration tab on said first flanged lateral edge and a corresponding registration gap on said second flanged lateral edge. 6) A roof ventilation system as recited in claim 5, further comprising a plurality of panels laid adjacent to each other, wherein said registration tab registers with said corresponding registration gap of an adjacent panel when said panels are laid upon the roof framing members. 7) A roof ventilation system as recited in claim 5, wherein said first flanged lateral edge include a plurality of said registration tabs. 8) A roof ventilation system as recited in claim 7, wherein said panel is secured to the roof framing members through said plurality of registration tabs. 9) A roof ventilation system as recited in claim 5, where said second flanged lateral edges include a plurality of registration gaps. 10) A roof ventilation system as recited in claim 1, whereby when said first and second lateral edges are secured between the top of roof the roof framing members and the roof sheathing, a vent channel is formed between the roof sheathing and said panel. 11) A roof ventilation system as recited in claim 1, wherein said reinforcing element includes at least one stiffening wall that extends upward from and substantially perpendicular to the roof side to provide stiffness. 12) A roof ventilation system as recited in claim 1, wherein said panel further includes a baffle flap at said first end. 13) A roof ventilation system as recited in claim 12, wherein said baffle flap is connected to said first end by a hinge. 14) A roof ventilation system as recited in claim 1, wherein the width of said panel is substantially equal the space between roof framing members plus the thickness of two roof framing members. 15) A roof ventilation system as recited in claim 1, wherein said panel further includes a first interlocking element at said first end. 16) A roof ventilation system as recited in claim 15, wherein said first interlocking element includes a channel support. 17) A roof ventilation system as recited in claim 15, wherein said first interlocking element includes a reinforcing element spanning between said first and second flanged lateral edges. 18) A roof ventilation system as recited in claim 1, wherein said panel further includes a second interlocking element located adjacent to said second end. 19) A roof ventilation system as recited in claim 17, wherein said second interlocking element includes a channel support. 20) A roof ventilation system as recited in claim 17, wherein said second interlocking element includes a reinforcing element spanning between said first and second flanged lateral edges. 21) A roof ventilation system as recited in claim 1, further comprising a continuation component installed along the length of the roof framing members to extend the length of said vent trough. 22) A roof ventilation system as recited in claim 21, wherein said continuation panel has a first interlocking element at said first end that interlocks with a second interlocking element of a said panel. 23) A roof ventilation system for mounting between roof framing members and roof sheathing, comprising: a panel including: a) a roof side, an attic side, a first end and a second end; b) a vent trough formed from a first flanged lateral edge, a middle section and a second flanged lateral edge, wherein each said flanged lateral edge has a canted section, wherein each said flanged lateral edge has a flat edge section extending outward parallel to said middle section; and c) an array of vent channel supports dimensioned to extend from said middle section to a plane defined by said flat edge sections of said first and second flanged lateral edges, each said vent channel support intersecting the plane at a single apex. 24) A roof ventilation system as recited in claim 23, wherein each vent channel support is surrounded on all sides by said middle section. 25) A roof ventilation system as recited in claim 23, wherein said array of vent channel supports are at least one from the group including domes, cones and pyramids. 26) An insulation dam for creating a barrier between attic space and eave space, the attic and eave space bounded by roof framing members and roof sheathing, said insulation dam comprising: a) a flat and rectangular top panel having a top edge, a bottom edge, a first top panel edge and second top panel edge, said top panel having a width that spans greater than the width between the roof framing members; b) a baffle flap having a top blocking edge and opposite frame edges, said blocking panel attached at said top blocking edge by a hinge to said bottom edge of said top panel; said blocking panel spanning the width between the roof framing members; c) a baffle flap tab extending from each of said opposite frame edges of said baffle flap, each said baffle flap tab having a fold line where it meets each said opposite frame edge, whereby when said insulation dame is installed each said baffle flap tab bends toward the eave space and orients to attach substantially parallel to the inside of the roof framing members; and d) a baffle flap gap between said top panel and each said baffle flap tab, said baffle flap gap dimensioned so that said baffle flap tabs do not stick into the plane of the roof sheathing when secured to the roof framing members. 27) An insulation dam as recited in claim 26, wherein the width of said top panel is less than the width between roof framing members plus the width of two roof framing members. 28) An insulation dam as recited in claim 26, wherein each said baffle flap tab is a rectangular baffle flap tab. 29) An insulation dam as recited in claim 26, wherein said hinge is a living hinge. 